The present invention relates to a cellular telephone antenna, and more particularly to a bi-frequency cellular telephone antenna which uses two coils to form a bi-frequency antenna structure.
Conventional cellular telephones are specifically designed for a particular frequency. There are disclosed a variety of advanced cellular telephones with bi-frequency antenna capable of matching GSM900 and GSM1800. FIGS. 1 and 2 show a bi-frequency antenna for a cellular telephone according to the prior art. This structure of bi-frequency antenna uses a conductive plate 10 instead of a winding. The conductive plate 10 is made of a thin sheet of metal by stamping, having a wave-like vertical section 11, and a wave-like horizontal section 12. When the conductive plate 10 is made, it is adhered to the periphery of a shaft 13. Because the stamping die for making the conductive plate 10 is of high precision, the cost is high. Further, adhering the conductive plate 10 to the periphery of the shaft 13 is not an easy job.